Three‐Dimensional Anisotropy of Turbulence at Ion‐Scales in the Magnetotail's Bursty Bulk Flow

Abstract

Using the data from Magnetospheric Multiscale mission, we statistically investigate the anisotropy of turbulence within bursty bulk flows (BBFs) in the Earth's magnetotail. By computing five‐point second‐order structure functions, we reveal the three‐dimensional anisotropy and scaling properties of turbulence at ion scales. In the coordinate system (), the characteristic lengths of turbulence eddies for both total and perpendicular magnetic field fluctuations exhibit at ion‐scales. The anisotropy scaling relations for the total magnetic field are and . For the perpendicular magnetic field fluctuations, the scaling relations are and . In addition, the parallel magnetic field fluctuations features , with scaling relations given by and . The observed scaling laws suggest that the turbulence anisotropy in BBFs exhibits a weak scale dependence. These results provide critical observational evidence for turbulence modeling and can deepen our understanding of the turbulence anisotropy at kinetic scales in plasma turbulence.